91 4.3 omc cobra starts runs the will not start

[cybro]

hello new here . hope a omc master is around . my 91 four winns 4.3 starts and it runs fine , i turn it off and it will not start back up right away . it will start back up but it is sparatic. you see after getting it ready to use the slave solenoid for the starter was starting to act up clicking sometimes and not starting .so i replaced it . started it up ran fine killed it and then started it back up a couple times then it just would not start everytime cranks away but will not start up then after a couple minuites or tries it starts . kill it then it won't start . i replaced the coil last year and the boat worked 8 hours with no problems then winerized and put away. i have noticed that at startup the alternator is not putting out enough juice about 12.4 at idle and 13.9 at about 1200 rpm i am now going to replace it as it seems this is an origanal part from 1991 . all my connections on the battery are new and tight . all connections are coated with dielectric grease and ther is no corrosion . this boat only has 200 hours and looks like new always maintained and always inside under wraps . so with this history ive explained is it possible this alternator could cause this sparatic starting ??? i'm sure it is something simple a module or something just lookin for some guidance

 

[Hansolo99]

Re: 91 4.3 omc cobra starts runs the will not start

Sounds like maybe a carb problem? I had a Nautique with something similar. However if I would give it FULL throttle and crank it for a short time it would start. It does crank correct??

 

[WAVENBYE2]

Re: 91 4.3 omc cobra starts runs the will not start

Mine was doing the same thing as far as starting then didn't start, even died out of nowhere while running at idle speed, turned out to be a loose wire on my fuel pump, not saying that could be your problem, but it sounds like your getting plenty of juice, what about the choke, have you checked these things out to, just trying to give you some new ideas maybe you haven't checked yet, they are also simple troubleshooting, fuel pump working OK???
I might not be a Master OMC mechanic but I am turning out to be quite the Master parts replacer

 

[Hansolo99]

Re: 91 4.3 omc cobra starts runs the will not start

I might not be a Master OMC mechanic but I am turning out to be quite the Master parts replacer

LOL!! Yes the CHOKE, check that. Mine was stuck for some reason. A new 2000 Ski Nautique $25,000.00 boat with a STUCK CHOKE! Check the little things first....

 

[cybro]

Re: 91 4.3 omc cobra starts runs the will not start

well it has a mechanical fuel pump . choke is fine . this thing will start with just a touch and idles fine kill it and it just cranks wait a min or 2 crank and starts at a twist of the key no long cranking . the boat has always started this way real easy till now it's just strange i'm a autobody/mechanic and i understand all the basics . but when it comes to boats some things are a little different from cars in the electrical . as i mentioned before the alternator is i belive getting old . and though it doesen't make any noise i did notice that after running it for about 5 mins or so it was really hot . just wondering scince it is connected to the ignition if it is creating a voltage draw that is intermitint and causeing it to sometimes not start . i used a test light on the coil and it lit it up while cranking but it did not start .

 

[WAVENBYE2]

Re: 91 4.3 omc cobra starts runs the will not start

OK your a mechanic with good skills, hope I didn't offend, My questions are real! Let me ask you this, do you think possably that maybe fuel isn't going through the line, Maybe turn the key to on for a few seconds to allow the fuel to get to your carb, before you crank her over completely, maybe give it a few seconds, then crank her over, I am sure you know what I mean

 

[Louisianagames]

Re: 91 4.3 omc cobra starts runs the will not start

I would go the other way..Check all grounds. clean them and then give it a try.

 

[cybro]

Re: 91 4.3 omc cobra starts runs the will not start

i will look into the grounds again . 2 years ago i had to replace the ground terminal on the battery because it gave the same symptoms as it is doin now it was a little corroded and sometimes it would crank but not start . replaced terminal and no prob for 2 years . i'll look at the block ground havent checked that yet . maybe i will replace both battery terminals with the post type as the ones that are on it now are for the post with wing nuts . maybe even though the terminal is relatively new it is not grounding properly . but i really don't think this is the prob . there has to be a old omc pro out there on this forum who has seen this as this setup on this boat was poular back in the ninetys .

 

[cybro]

Re: 91 4.3 omc cobra starts runs the will not start

well found the problem after reading thread after thread last night found nothing . went out this morning went thru everything all connections then i checked the charge status on the battery under load and found it needed to be charged it was a little weak . i set my charger to 10 amps charge for 2 hours . the battery is a 27 line interstate marine crank . 750 MCA. hooked the battery back up and it cranked right up and has not failed yet . i have started it about 20 times now no problems ..alternator not getting hot anymore . i guess the amperage drop was just enough to keep it from starting every time and the alternator was workin a lot harder trying to charge the battery . i also change my battery connection terminals to the large size post and use the wingnut post for other electronics i think it a better deal than having all connections on the wing nut post.